Ok guys I just got worked getting car smogged. Here are the results: (MAX, Gross Poluter, Me)

HC: 108, 283, 292 15 MPH
83, 233, 250 25 MPH

CO: .71, 2.21, 6.83 15 MPH
.58, 2.08, 6.18 25 MPH

NO: 1020, 1957, 256 15 MPH
880, 1757, 186 25 MPH

As you can see my CO and HC are WAY above the legal limit. Now my datamaster is giving me 160 BLM's across the board, what could cause it to say I'm running lean when it's dumping so much fuel into the engine? Does the VSS have anything to do with it? I really need some help guys I am in deep **** if I can't get this thing passed soon. Thanks.

Jim

 

Three things: false O2 readings from a pinched wire or such, a bad O2 sensor not working (very common), or a vacuum leak. None of these can be helped by prom burning though.

 

But if that was the case the computer wouldn't be seeing a lean condition it would sense a rich condition and start trying to pull fuel out, leading to a BLM of like 108 at the other end of the spectrum. Right?

BTW, the O2 sensor is only a few months old and I have about 40 Kpa @ idle. I will post the bin I'm using right now if that will help anyone, and If I can figure out how to get infor off my laptop (3.5" floppy is broken) I will post the datamaster logs as well.

 

No, not right. ECM sees lean and adds fuel in closed loop and vice versa. If it saw lean and took fuel out it would defeat the purpose.

 

I think we are saying the same thing. Bottom line the car is running rich, very rich. The Smog check proves that (high HC and CO). But the computer is reading a lean condition (BLM maxed out 160) and trying to add more fuel to the combustion process. These seem to be in stark constrast to each other.

Hectorsn, Thank you for your responses I am not trying to start an arguement this is just the way I understand it. Maybe I have the concept of the BLM's reversed?

Thanks again for your help.

Jim

 

Here is the bin file I am using:

 

Me neither, I hate arguments. Total waste of time. I think you have a grasp on the BLM thing but are having trouble understanding what's going on. Basically in closed loop the ecm is going to look at O2 readings and go from there. I work on cars for a living and have seen a grounded O2 signal wire, a bad (only indicating lean) O2 sensor, and big vacuum leaks or exhaust leaks cause the ECM to see a lean condition when in fact the car is rich. But since it is mostly relying on O2 feedback and the O2 line is reporting lean.... BAMM, high BLM to compensate. There could be other things like a bad ecm or ground somewhere or even a bad prom but my money is on the three suggestions above. If you can, try and make the ecm stay in open loop and see if it runs better. It is not a fix but.....

 

Ok, I have been running this over in my head and I think I understand what you are saying. A vacum leak would cause the engine to sense a lean condition and add way too much fuel to an otherwise healthy combustion process, while sending high BLM counts to the diagnostic software. Someone please validate this. Thanks.

Ok I just read your post thanks I think I get it now. I just have to go find my vacum leak.

Could a exhaust leak cause a lean condition as well?

 

An exhaust leak could, but would have to be pretty bad, most of the time your exhaust has positive pressure in it so gasses flow out the leak not in.

 

Well, just to give you guys an update as was the consensus with the people I talked to it was a massive exhaust leak, right below the O2 sensor. replaced the doughnut and all the BLM's fell into range. Not 128 but I now have rich and slightly lean conditions that I can fix instead of BLM's of 160 everywhere. Thanks again for your help guys now on to tuning so I can pass that smog check.